Sarah Zhang

Human bodies are of course not built for microgravity. We've long known that astronauts lose bone mass, but studying the process in space is tricky. The International Space Station is getting its first medical X-ray to examine on-board lab mice and rats. But making a space X-ray machine was no easy task.

The Bone Densitometer developed by Techshot will finally let astronauts study how rodents lose bone mass in real-time. It's essentially a modified version of a common, microwave-sized lab machine, but getting it to work in space required some clever engineering. For one, you don't want a mouse floating around in the machine, so the tray has a sticky, reusable, Post-it note-like surface. As New Scientist explains, some basic components were also replaced to live up to NASA's space safety standards.

For example, the scanner's wires are normally insulated with polyvinyl chloride. This material can produce a toxic gas when heated, a serious hazard in the cramped quarters of the ISS. The space-ready scanner uses Teflon instead. And stainless steel components replaced any made of tin or zinc, as these metals can grow slender crystalline "whiskers" that might break off and cause damage.

The Bone Densitometer—along with 20 live mice and rats—is expected to blast off in August aboard the newt SpaceX next cargo supply trip. The rodents will have a couple of months to acclimate to space (and lose bone mass) before experiments start in December. [New Scientist]